Could Babies Conceived in Winter Be More Likely to Have Learning Disabilities?

Here's interesting news for anyone currently trying to conceive: According to a group of researchers from the United Kingdom, a mom-to-be's exposure to sunlight affects more than just her skin—it might even influence her baby's risk of developing a learning disability.

A new study finds a surprising link between season of conception and fetal brain development. Babies conceived during the winter are at greater risk—and it appears to have everything to do with the sun. Sunlight causes the body to produce vitamin D, which plays a major role in brain development.

This finding comes after lots of thorough analysis: Researchers looked at data from 801,592 children in Scotland who were conceived during the winter months. Nearly 9 percent of these children had learning disabilities—a step up from the 7.6 percent learning disability rate seen in children born between July and September.

There is a catch, though: The study's authors didn't actually assess vitamin D levels in their subjects. Still, they do believe this factor seems more plausible than any other. This isn't the first time a study has found risks associated with low maternal vitamin D levels: We've also reported that the vitamin can strengthen a baby's bones, reduce allergy risks, and even make childbirth less painful (yes, really).

Researchers point out that there tends to be a real lack of sunlight in the U.K. from January to March, which causes vitamin D production to suffer. Month of conception matters because much of the fetus's brain development takes place in those first three months of pregnancy.

This particular study appears in the August 23 issue of the American Journal of Epidemiology, but the research was carried out in children born before 2012, when new guidelines urging pregnant women to take vitamin D supplements were released. Would the data have looked different had more mothers been taking supplements? Possibly.

"The results of this study show that if we could get rid of the seasonal variation, we could prevent 11 percent of cases of learning disabilities," Jill Pell, the study's co-author and director of the University of Glasgow's Institute of Health and Wellbeing, said in a news release for the study, according to HealthDay. "It is important that pregnant women follow the advice to take vitamin D supplements and also that they start supplements as early in pregnancy as possible; ideally when they are trying to get pregnant."

Of course, talk to your ob-gyn before starting any type of supplementation when you're pregnant or TTC!